An aqueous solution of `CuSO_(4)` is electrolyszed using `Pt` electrodes in one case and `Cu` electrodes in another case. What are the products of electrolysis in both the cases ?

Explanation

`a.` When `Pt` electrodes are used `:`
At anode `:H_(2)O rarr 2H^(o+)+(1)/(2)O_(2)+2e^(-)`
[Since oxidation potential of `H_(2)O gt` oxidation potential of `SO_(4)^(2-) "ion"]`
At cathode `:Cu^(2+)+2e^(-) rarr Cu`
( Since reduction potential of `Cu gt` reduction potential of `H_(2)O)`.
`b.` When `Cu` electrode are used `:`
At anode `:Cu` dissolves into solution to form `Cu^(2+)` ions.
At cathode `:Cu` is depostited as cathdoe.
Since both the reduction and oxidation potential of `Cu^(2+)` and `Cu` is greater than that of `H_(2)O`.